I use the term "command mood" instead of the more common
"imperative mood" to translate Zamenhof's modo ordona, since -u
covers a much wider range of uses than the traditional Western
imperative; in fact, it takes on many of the jobs ordinarily done
by the subjunctive (which does not exist as a separate entity in
Esperanto -- for which generations of Latin students may give
thanks!). Kalocsay and Waringhien refer to this form, in the
Plena Analiza Gramatiko, as the "volitive mood."

The Bulgarian Esperantologist Atanas Atanasov denies the existence
of passive verb forms in Esperanto -- and I find myself agreeing
with him. Use of the participial suffixes may be better understood
if you consider them as means of transforming verbs into
adjectives, not as parts of speech in themselves. The Western
passive voice is shown, as Zamenhof says, by coupling the verb
esti = "to be" with the "passive participles"; but these are not
really compound verb forms, merely the copula linked with an
adjective.
EXAMPLESLa sandviĉo estis manĝata
= The sandwich was (in a state of being) eaten.
La sandviĉo estas manĝita
= The sandwich is (in a state of having been) eaten.
La sandviĉo estis manĝita
= The sandwich was (in a state of having been) eaten.
La sandviĉo estos manĝota
= The sandwich will be (in a state of) going to be eaten.
Use of such forms is rare in Esperanto -- even rarer than it is
in English, where Strunk & White advise against them. Ordinary
passives can easily be converted into ordinary active sentences
in Esperanto, sometimes with the inversion that the -n ending
permits, and the pronoun oni makes translation of even agentless
passives as active very easy. William Auld, in his 100-page epic
poem La Infana Raso, doesn't use the passive once. Bureaucratese
is rare in Esperanto.
EXAMPLESLa katon persekutis la hundo
= The cat was chased by the dog.
Oni pafis la hundon
= The dog was shot.

While the particles anstataŭ (instead of) and krom (besides, in
addition to) are generally classified (by analogy with their
equivalents in Western languages) as prepositions, their behavior
is more like that of coördinating conjunctions such as kiel.
So many Esperanto speakers will add the -n ending to the objects
of these "prepositions" when they coordinate with another word
that has an -n ending.
EXAMPLESMi amis ŝin anstataŭ li
= It was I, not he, who loved her.
Mi amis ŝin anstataŭ lin
= I loved her, not him.

The problem arises when learning the words through the medium of English; it is
often difficult to remember whether the word that means "to drown" means "to die
of suffocation in liquid" or "to kill by suffocating in liquid". When you encounter
such words, it is best to remember their meanings -- not their English language
equivalents.